Enforcing federal law to keep medical marijuana dispensaries away from schools is a "core responsibility" of federal prosecutors -- and it will continue, U.S. Attorney John Walsh wrote in a letter to Boulder County District Attorney Stan Garnett.

The letter, released Wednesday, comes in response to a letter Garnett sent Walsh last week in which he said dispensaries that otherwise comply with state and local law should not be targeted for federal enforcement. Garnett said federal resources should be reserved for large-scale drug trafficking, terrorism and organized crime, and local regulations were working well to control the industry.

U.S. Attorney John Walsh's letter to Boulder District Attorney Stan Garnett

The U.S. Attorney's Office has been sending letters to Colorado dispensaries located within 1,000 feet of schools that order the businesses to either move or close. Boulder ordinance says dispensaries cannot be within 500 feet of a school.

City records indicate there are 12 Boulder dispensaries within 1,000 feet of a school. No Boulder dispensaries were targeted in the first round of federal enforcement, but authorities have said more letters are in the works.

In his response, Walsh said he made the decision himself to go after dispensaries that are close to schools with full awareness of local conditions.

"One of (our) overriding interests -- not just for the federal government, but for Colorado government and for local government -- is the protection of children and young people from drugs and drug abuse, very much including marijuana abuse," Walsh wrote in the letter.

Walsh said the growth of the medical marijuana industry has been accompanied by "an alarming and substantial spike in marijuana abuse by children and young people." That increase required a response, he said.

Walsh noted that dispensaries targeted for enforcement have been given a 45-day grace period in which to close or move. So far, all compliance has been voluntary, and federal authorities haven't seized any property or drugs.

However, Walsh also said the targeted enforcement should not be interpreted as creating a "safe harbor" for medical marijuana dispensaries that are not within 1,000 feet of a school.

"This office will continue this program until all marijuana dispensaries in Colorado operating within 1,000 feet of a school have been warned and ceased operation," Walsh wrote in the letter. "To be clear, this program is not at the direction of Washington, D.C., but at my direction as U.S. Attorney and as a Coloradan, exercising the discretion that the Department of Justice has left local U.S. Attorneys to take local circumstances into account in determining how best to address the enforcement of federal laws against marijuana trafficking."

Walsh said his office has received an "outpouring of thanks and appreciation" for the effort to close dispensaries near schools.

"I believe that enforcing federal law to protect our children and young people from drug abuse is not only a legitimate use of federal resources, but a core responsibility for me and this office -- and I believe that is our duty as Coloradans as well," Walsh wrote.

Garnett confirmed that he received the letter, saying the response was respectful and part of an "appropriate conversation about prosecutorial priorities."

However, he said he had seen no evidence that dispensaries harm children and he continues to believe local authorities are best equipped to regulate the location of marijuana businesses.

"I've lived in Boulder County a long time, and the people of Boulder County care about all the right things, including their children," Garnett said. "I respect the U.S. attorney's position, but nobody should doubt that people in Boulder County care about protecting their children. If I had seen evidence that dispensaries were having an impact on children, I would be among many local leaders calling for additional regulations."

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